The protective effects of rutin on the liver, kidneys, and heart by counteracting organ toxicity caused by synthetic and natural compounds

Abstract Rutin is a flavonoid present in many plant species. Because of its antioxidant, anti‐inflammatory, and antiapoptotic properties, rutin is of interest for its potential protective effects against toxic agents. The hepatoprotective, renoprotective, and cardioprotective effects of rutin are reviewed. The antioxidant effects of rutin are elicited by enhancing antioxidant enzymes such as GST, GGT, CAT, GPx, SOD, and GR, activating the Nrf2/HO‐1 pathway, elevating GSH content, and the reduction in MDA. The anti‐inflammatory effects of rutin are mediated by the inhibition of IL‐1β, IL‐6, TGF‐β1, COX‐2, iNOS, TLR4, and XO. Rutin exerted its antiapoptotic effects by inhibition of free radicals, caspase‐3/‐7/‐9, hsp70, HMGB1, and p53, and the elevation of the antiapoptotic protein Bcl‐2. Rutin has potential therapeutic effectiveness against several toxicants, and its beneficial effects are more than likely mediated by its antioxidant, anti‐inflammatory, and/or antiapoptotic property.


| INTRODUC TI ON
Over the past several decades, there has been an increased interest in natural products due, in no small part, to their radical scavenging, anti-inflammatory, antidiabetic, and anticancer properties. The polyphenolic structure of flavonoids, a class of natural products, has been reported to be responsible for their therapeutic effects (Sharma et al., 2013;Yarmohammadi et al., 2021). Rutin (3′, 4′, 5, 7-tetrahydroxyflavone-3-rutinoside, Figure 1) is one of the more interesting flavonoids found in plants like buckwheat, passionflower, tea, and apples (Frutos et al., 2019;Hosseinzadeh & Nassiri-Asl, 2014;Rezvani et al., 2011). The concentration of rutin varies depending on the plant species, the plant part, and the geographical origin of the plant (Frutos et al., 2019).
Rutin exhibits protective effects on the heart (Li et al., 2020;Ma et al., 2017;Wang et al., 2017), the kidneys (Qu, Dai, Guo, et al., 2019;Qu, Dai, Lang, et al., 2019), and the liver (Lee et al., 2019;Zargar et al., 2017). The primary pharmacological effect and the underlying mechanism of rutin are enhancement of the antioxidant capacity via the nuclear factor-erythroid factor 2-related factor 2/ antioxidant response element (Nrf2/ARE); its anti-inflammatory effect via suppression of nuclear factor-kappa B (NF-κB), tumor necrosis factorα (TNFα), cyclooxygenase 2 (COX-2), and interleukin-6 (IL-6); and its antiapoptotic effect by inhibition of caspase-3/−9 and B-cell lymphoma 2 (Bcl-2) enhancement (Janbaz et al., 2002;Nafees et al., 2015). Rutin has also been shown to modulate dynaminrelated protein 1 (DRP1), which is an essential protein involved in the regulation of mitochondrial fission (Choi et al., 2021). Rutin has metal-chelating capabilities, thereby preventing metal ion-induced peroxidation (Frutos et al., 2019). Rutin is hydrolyzed and converted into quercetin and rutinose by the gut microflora. According to one dietary supplement database, over 860 rutin-containing products are available in the United States (Gullón et al., 2017). The potential protective effects of rutin against organ toxicity induced by both synthetic and natural compounds, with a focus on the liver, kidney, and heart as the major organs, will be reviewed.

| ME THODS
A comprehensive literature review was performed using the following keywords: "Rutin" and "Cardioprotective" OR "Hepatoprotective" OR "Nephroprotective" in the following databases: PubMed, Scopus, Medline, and Web of Science. All retrieved articles were reviewed to find relevant in vitro and in vivo studies published until February 2022. Only original articles were included. Duplicated, none relevant, and non-English language articles were excluded. Following these search criteria, we found 65 articles in the online databases, among which 10 were excluded for the following reasons: no innovative or influential content and inconsistent or arbitrary conclusions; the remaining 55 articles were included in the current review.

| The protective effects of rutin against hepatotoxicity
A major function of the liver is to detoxify chemicals. Drug-and chemical-induced damage is a common cause of the liver disease (Gu & Manautou, 2012). Numerous substances have been shown to have hepatotoxic properties, including ethanol, carbon tetrachloride, and acetaminophen (Nathwani & Kaplowitz, 2006). The mechanisms by which chemicals cause liver damage include oxidative stress induction, the production of proinflammatory mediators such as TNFα, NF-κB, COX, and nitric oxide (NO), and apoptosis.
The hepatoprotective effect of rutin is attributed to its antioxidant, anti-inflammatory, and antiapoptotic properties (Table 1).

| Ethanol
Chronic alcohol consumption is associated with liver disease, which can lead to a range of disorders such as steatosis, fibrosis, and carcinoma (Lee et al., 2019;Tang et al., 2013). Choi et al. (2021) demonstrated that rutin has a cytoprotective effect against hepatotoxicity induced by ethanol using HepG2 cells and zebrafish. The protective effect of rutin was associated with the inhibition of mitochondrial dynamics mediated by DRP1 in both zebrafish and HepG2 cells.
DRP1 is a member of the dynamin GTPase superfamily localized at the mitochondrial outer membrane site, where it regulates the fission of mitochondria and other related cellular processes. Their results indicated that rutin reduced steatosis induced by ethanol in the liver of zebrafish larvae. Rutin has also been shown to decrease the levels of several hepatic enzymes including aspartate transaminase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) in male rats. It reduced the ethanol-induced hepatotoxicity by enhancing antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-Stransferase (GST), and non-enzymatic antioxidants like glutathione (GSH). The hepatoprotective effect was confirmed by histological evaluation (Shenbagam & Nalini, 2011). The Nrf2/ARE pathway has been reported as an important signaling axis in preventing alcoholic liver damage. The protective effect of rutin against ethanol-induced toxicity in HepG2 cells has been reported to involve the enhanced expression of the Nrf2/ARE pathway (Table 1) (Lee et al., 2019).
The hepatotoxic effect of CCl4 has been attributed to the excessive production of free radicals. It has been demonstrated that F I G U R E 1 Chemical structure of the rutin TA B L E 1 Summary of the rutin-induced protective effects on the liver antioxidant-rich substances reduced CCl4-induced liver damage (Janbaz et al., 2002). Rutin administration in rats has been reported to ameliorate the oxidative stress induced by CCl4 via promoting CAT, SOD, GST, GSH-Px, and GSH, and by suppressing lipid peroxidation. Rutin also mitigated DNA fragmentation and oxidative damage to the DNA caused by CCl4, as well as increased the expression of p53 and CYP2E1 (Khan et al., 2012a). A study in BALB/c mice suggested that rutin administration attenuated the inflammation caused by CCl4 via the downregulation of NF-κB, TNFα, and COX-2. Rutin also suppressed the expression of transforming growth factor-β1 (TGF-β1). Additionally, rutin treatment increased the expression of Nrf2 and heme oxygenase-1 (HO-1) in the injured liver. Histological examination confirmed that rutin prevented or at least reduced the hepatocellular damage caused by CCl4 ( Table 1) (Hafez et al., 2014).  (Table 1) (Hafez et al., 2014).

TA B L E 1 (Continued)
showed mild degeneration in the hepatocytes in the rutin-treated rats with no necrosis, suggesting that rutin reduced the toxic effects of mercury in the liver (Table 1).

5-Fluorouracil is an antimetabolic anticancer agent and influences
the synthesis of DNA and RNA in both normal and tumor cells (Zhang et al., 2008). 5-Fluorouracil exposure elevated liver enzymes such as AST, ALT, LDH, and ALP which were reversed by rutin. Moreover, rutin diminished malondialdehyde (MDA) levels and enhanced the GSH content and GPx activity. Rutin also modulated apoptotic markers by reducing caspase-3 and increasing Bcl-2. The arrangement of the hepatocytes in the liver was almost normal (

| Cyclophosphamide
Cyclophosphamide is an anticancer medication used to treat a variety of human cancers and other diseases, including systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis (Naicker et al., 2021). The use of cyclophosphamide, however, is restricted due to its toxicity including nephrotoxicity, hepatotoxicity, cardiotoxicity, and immunotoxicity Administration of rutin to male Sprague-Dawley rats ameliorated the cyclophosphamide-induced hepatotoxicity by diminishing inflammatory markers such as TNFα, IL-6, p38 MAPK, NF-κB, inducible nitric oxide synthase (iNOS), and COX-2 (Nafees et al., 2015). The histopathological findings confirmed these results (Nafees et al., 2015). The authors suggested that rutin might attenuate oxidative stress and inflammation induced by cyclophosphamide by suppressing the p38 MAPK/NF-κB pathway (Table 1; Figure 2).

| Methotrexate
Methotrexate is a cytotoxic drug widely used in chemotherapeuticbased cancer treatments. It has a noxious effect, however, on the liver, especially when given in high doses for long periods (Bath et al., 2014).
A study by Erdogan et al. (2015) reported that methotrexate administration provoked liver toxicity reflected in elevated AST and ALT and decreased SOD and GSH-Px. Rutin treatment reversed the effect induced by methotrexate. The hepatocyte vacuolization, sinusoidal dilation, and radial arrangement disruption induced by methotrexate in female Wistar rats were reversed by rutin (Table 1; Figure 3).

| Thioacetamide
Thioacetamide is an organosulfur chemical known to cause severe hepatotoxicity in animal models (Moustafa et al., 2014). In an in vivo study, rats exposed to thioacetamide had elevated AST, ALT, ALP, LDH, total bilirubin, and DNA fragmentation. Rutin administration before thioacetamide resulted in a significant reversal of liver damage. Histopathological examination of the liver showed no significant difference between the control and rutin-treated animals (Table 1) (Zargar et al., 2017).

| Tert-butyl hydroperoxide
Terutin-butyl hydroperoxide (t-BHP), an organic peroxide, is used to produce propylene oxide by the oxidation of propylene with tertbutyl hydroperoxide. t-BHP is also an environmental oxidative stress inducer that has been reported to generate ROS (Mir et al., 2021).

| Oxytetracycline
Oxytetracycline is a broad-spectrum antibiotic used to treat various infections. Its usage can result in significant hepatotoxicity. Londero et al. (2021) showed that rutin administration reversed the hepatotoxicity induced by oxytetracycline in silver catfish by improving the oxidized glutathione (GSSG)-to-GSH ratio, G6PDH activity, and several other antioxidant enzymes such as SOD, GPx, and GR.

| Deltamethrin
Deltamethrin is a synthetic pyrethroid insecticide used worldwide to control mosquitoes, flies, and insects in general .

| The protective effect of rutin against nephrotoxicity
A primary function of the kidney is homeostasis. In this regard, the kidneys control body fluid levels, electrolyte balance, acid-base balance, hormone secretion, blood pressure, and toxic metabolites excretion (Molaei et al., 2021

| Vancomycin
Vancomycin is an antibiotic used to treat gram-positive bacterial infections. Vancomycin, however, can cause nephrotoxicity F I G U R E 2 A schematic illustration of the rutin-induced protective effects against toxic agents. ↑ and → present the promote/activate, ⊥ and ↓ present the inhibitory/suppressive effects (Brunetti et al., 2020). In a study conducted by Qu et al., male Wistar rats were exposed to vancomycin and rutin. Co-administration of the two chemicals induced a significant suppression in blood urea nitrogen (BUN), creatinine (Savi et al., 2017), and N-acetylbetad-glucosaminidase (NAG), all of which were elevated in the vancomycin-treated animals. Co-administration also restored several renal functional markers (Qu, Dai, Lang, et al., 2019). The

| Gentamicin
Gentamicin is an antibiotic that is useful in treating severe sepsis.
However, its usage is restricted due to the development of ototoxicity and nephrotoxicity (Morin et al., 1980). Gentamicin-induced F I G U R E 3 A schematic diagram of the rutin-induced protective effects against toxic agents on the liver, kidneys, and heart. → and → present the promote/activate, ⊥ and ↓ present the inhibitory/suppressive effects TA B L E 2 Summary of the rutin-induced protective effects on the kidney nephrotoxicity is related to oxidative stress and inflammatory cascades (Sahu et al., 2014). In an in vivo study, rutin decreased gentamicin-induced nephrotoxicity by diminishing MDA levels while enhancing SOD, CAT, and GPx activities, as well as GSH levels. The suppression of iNOS, cleaved caspase-3, and light chain 3B (LC3B by rutin was confirmed by immunohistochemical staining). Rutin also exhibited antioxidant, anti-inflammatory, antiapoptotic, and antiautophagy properties (Table 2) (Kandemir et al., 2015).

| Cisplatin
Cisplatin is used to treat head, ovarian, neck, colon, and testicular cancers. However, the use of cisplatin is limited due to its side effects, such as nephrotoxicity, ototoxicity, neurotoxicity, and car-  (Table 2).

| Potassium bromates
Potassium bromate is a food additive and a by-product of water disinfection. In both humans and experimental animals, potassium bromated has been shown to induce multiorgan toxicities (Shanmugavel

| Mercuric chloride
Mercury is a hazardous environmental and industrial contaminant that occurs in a range of chemical forms, including elemental, organic, and inorganic mercury (Bernhoft, 2012). Enhancement of MDA levels, suppression of antioxidant enzyme activities such as CAT, SOD, GPx, and GSH, and production of inflammatory factors like TNFα, Bcl-3, IL-1β, NF-κB, and IL-33 have all been reported to be involved in mercury-induced nephrotoxicity in rats. Rutin has been shown to completely or partially reverse these changes ( Figure 2). Rutin has also been reported to enhance the activities of MAPK 14 and myeloperoxidase (Caglayan, Kandemir, Yildirim, et al., 2019). Mercury-induced apoptosis has been reported to be reversed by rutin supplementation through the mitigation of oxidative stress, apoptosis, and inflammation (Table 2) (Caglayan, Kandemir, Yildirim, et al., 2019).
Aquaporins (AQPs) are membrane protein channels involved in water transfer and, in some cases, the migration of small ions across cell membranes (Caglayan, Kandemir, Yildirim, et al., 2019).

| Lipopolysaccharide
Lipopolysaccharide (LPS) is the major component of the outer membrane of gram-negative bacteria that causes strong inflammatory and immunological responses in animals and is thought to be implicated in the pathophysiology of sepsis-induced acute kidney injury (Nozaki et al., 2020). It has been shown that rutin administration restored kidney injury induced by LPS in C57BL/6 mice as assessed by lower serum levels of Cr and BUN. The nephroprotective effect of rutin against LPS was reported to be mediated through the inhibition of toll-like receptor 4 (TLR4), COX-2, sirtuin 1 (Sirt1), TNFα, IL-6, and caspase-3 (

| Lead
Lead is a heavy metal contaminant with multiple industrial uses.
Exposure to lead can cause a variety of adverse effects including nephrotoxicity resulting in substantial changes in the structure and function of the kidneys (Shafiekhani et al., 2019). It has been reported that pretreatment of male Sprague-Dawley rats with rutin elicited a protective effect against lead-induced toxicity by elevating antioxidant parameters such as GSH, CAT, GPx, and SOD (Ansar et al., 2016). Additionally, following rutin treatment in lead acetatetreated rats, there was a decline in BUN, Cr, and uric acid, which was increased following lead acetate exposure only in rats (Table 2) (Ansar et al., 2016).

| Hexachlorobutadiene
Hexachlorobutadiene is a halogenated aliphatic chemical used in the industry for elastomers, rubber, heat-transfer liquids, transformers, hydraulic fluids, and insecticide, herbicide, and fungicide formula-

tions. Rutin administration 1 h before hexachlorobutadiene injection
reversed the nephrotoxicity as reflected in a decrease in lipid peroxidation, serum Cr, urea, and both urine glucose and protein in female Wistar rats (Table 2) (Sadeghnia et al., 2013).

| Deltamethrin
Deltamethrin is a synthetic pyrethroid insecticide .
The administration of deltamethrin has been shown to induce hepatotoxicity and nephrotoxicity in rats (Küçükler et al., 2021).
Pretreatment with rutin reversed the deltamethrin-induced toxicity by decreasing TNFα, IL-1β, p38 MAPK, COX-2, and iNOS in the liver and kidneys, again reflecting the anti-inflammation property of rutin.

| The protective effect of rutin against cardiotoxicity
Cardiotoxicity is the alteration, injury, and/or dysfunction of the heart that may develop following drug, heavy metal, pesticide, or toxicant exposure. Various mechanisms have been suggested for chemicals-induced cardiotoxicity, including apoptosis induction, cytokines release, ROS generation, and suppression of the antioxidant system (El-Nahhal & El-Nahhal, 2021;Zhang, Zhu, et al., 2019). Due to its anti-inflammatory, antiapoptosis, and antioxidant properties, rutin may have the potential to alleviate some of the cardiotoxicity caused by such agents (Table 3).

| Cisplatin
Cisplatin is an anticancer drug used to treat a variety of cancers.
However, its application has been reported to induce several toxicities including nephrotoxicity and cardiotoxicity (Karimi et al., 2005).

| Doxorubicin
Doxorubicin is an antineoplastic drug used to treat a range of malignancies such as carcinomas, sarcomas, and hematological cancers. However, doxorubicin can induce cardiotoxicity (Koleini & Kardami, 2017). Rutin administration to mice exposed to doxorubicin improved the left ventricular ejection fraction (EF) and mitigated or at least reduced cardiac fibrosis, LC3 II, ATG5, and P62 expressions, and autophagic markers (Roohbakhsh et al., 2016).
Rutin also reduced the apoptotic markers, Bax and caspase-3, and increased antiapoptotic Bcl-2 (Ma et al., 2017). Sadzuka et al. (1997) demonstrated that rutin administration to mice prevented doxorubicin cardiotoxicity through enhancement of GSH-Px activity, and suppression of lipid peroxidation and creatine kinase (CPK) in heart tissue (Table 3).

| Pirarubicin
Pirarubicin is a member of a group of cell cycle nonspecific anthracycline anticancer drugs. Cardiac toxicity, alopecia, and digestive system disturbance have been reported following treatment with pirarubicin (Wang et al., 2020). Rutin decreased the pirarubicininduced electrocardiogram abnormalities and cardiac dysfunction in rats. The serum levels of MDA, B-type natriuretic peptide (BNP), CK-MB, cardiac troponin T (cTnT), LDH, and SOD were attenuated following rutin exposure in pirarubicin-treated rats. Rutin also increased the Bcl-2/Bax ratio and suppressed the JNK and caspase-3 protein content in cardiac tissue . JNK is a key protein in the MAPK pathway that plays an important role in the cell cycle, apoptosis, and cell stress (Lou et al., 2005). Rutin treatment of HL-1 cells exposed to pirarubicin reduced oxidative stress. In addition, rutin activated the JunD signaling pathway by downregulating miR-125b-1-3p expression that plays an essential role in cancer progression and immunosuppression (Li et al., 2020). JunD is a transcription factor that belongs to the activating protein-1 (AP-1) family and serves as an activator or inhibitor of the expression of multiple genes (Good et al., 2019).
Rutin inhibited apoptosis through the upregulation of Bcl-2 and the downregulation of Bax, caspase-3, and caspase-9 in H9c2 cells  (Fei et al., 2019). Treatment of H9c2 cardiomyoblasts with rutin prevented the pirarubicin-induced reduction in cell viability and at the same time upregulated TGF-β1, p38 MAPK, cleaved caspase-9, caspase-7, and caspase-3 ( Figure 2). These results suggested that rutin promoted its cardioprotective effects through the inhibition of ROS generation and the reduction of cell apoptosis by the TGF-β1/ p38 MAPK signaling pathway (Table 3) .

| Isoproterenol
Isoproterenol is a potent nonselective beta-adrenergic agonist that is used to induce myocardial infarction in animal models (Sood et al., 2005).

| Streptozotocin
Streptozotocin (STZ) can be used to induce experimental diabetes and cardiotoxicity (Umbarawan et al., 2020). STZ exposure produces cardiomyopathy through suppression of the antioxidant capacity and the enhancement of inflammatory cytokines in rats (Saklani et al., 2016). These changes were ameliorated by rutin treatment (Saklani et al., 2016). Treatment with rutin also ameliorated ischemia/ reperfusion-induced myocardial infarction, reduced MDA, increased SOD and CAT, and regulated heart rate in STZ-treated rats (Table 3) (Annapurna et al., 2009).

| Lipopolysaccharide
Lipopolysaccharide has been reported to cause organ damage including the heart and brain by induction of an inflammatory re-

TA B L E 3 (Continued)
LPS has been hypothesized to involve several mechanisms, including enhancement of matrix metalloproteinases 2 and 9 (MMP-2 and -9), proinflammatory cytokines (TNFα and IL-6), and suppression of antioxidant enzymes (SOD and CAT). These changes were reversed by rutin pretreatment in male mice (Table 3) (Xianchu et al., 2018).

| Cobalt
Cobalt is an essential trace element with both industrial and biological applications. However, excessive concentrations of cobalt are known to elicit cardio-renal dysfunctions (Linna et al., 2004). Rutin

| Aluminum phosphide
Aluminum phosphide, a pesticidal fumigant, has been shown to induce cardiotoxicity by generating oxidative stress and mitochondrial damage (Hosseini et al., 2020). Rats exposed to aluminum phosphide had suppressed heart rate and ST elevation, and increased GSH, TNFα and IL-6, MDA and caspase-3 levels, and SOD activity. Rutin ameliorated these changes ( 2.3.10 | Sodium fluoride Barbier et al. (2010) reported that sodium fluoride exposure resulted in lower cognitive function ability, intelligence quotient, mental disorders, and cardiovascular and hepatic toxicities. Umarani et al. (2015) demonstrated that sodium fluoride treatment elevated lipid peroxidation, total cholesterol, TGs, white blood cells, and erythrocyte sedimentation and decreased high-density lipoprotein (HDL), hemoglobin, red blood cells, mean corpuscular volume, and mean corpuscular hemoglobin in rats. These alterations were reversed by rutin (Table 3).

| D ISCUSS I ON AND CON CLUS I ON
Rutin has various pharmacological effects. In the present article, we have reviewed studies dealing with the protective effects of rutin on the heart, liver, and kidneys. Previous studies have shown that rutin can induce significant protective effects against synthetic chemicals and toxins with diverse mechanisms of toxicities. The beneficial effects of rutin are mainly associated with its antioxidant, anti-inflammatory, and antiapoptotic effects. The antioxidant effect of rutin has been reported to involve enhancing the activity of enzymes such as SOD, GST, GGT, CAT, and GPx GR, and inducing the Nrf2/HO-1 pathway. The anti-inflammatory effects of rutin are mediated by the inhibition of well-known proinflammatory mediators and molecules such as IL-1β, IL-6, TGF-β1, COX-2, iNOS, TLR4, and XO. Inflammation and oxidative stress are processes that predispose tissues to malfunction and may end with the destruction of the target tissue. So, reduction in inflammation and oxidative stress reduction are key interventions in alleviation of such toxic effects.
In addition, rutin has been reported to exert its antiapoptotic effects by inhibiting apoptotic molecules such as caspase-3/-7/-9, and the elevation of antiapoptotic proteins including HMGB1 and Bcl-2. The beneficial effects of rutin on the heart, liver, and kidneys have been confirmed by histopathological examinations in a variety of studies. Rutin elicited significant cardioprotective, nephroprotective, and hepatoprotective effects that were mainly mediated by its antioxidant and anti-inflammatory properties. Considering these findings, further evaluation of this natural compound's ability to overcome the toxic effects of various toxicants is recommended.
This review summarized the findings of several important studies focusing on the protective effects of rutin against chemical and natural toxins. Based on the results, rutin could be a promising component in the prevention and treatment of several toxicities, including hepatotoxicity, nephrotoxicity, and cardiotoxicity, and protect organs against many agents that produce free radicals. Although the biological effects of rutin on ROS-induced skin aging have been reported in a human study, further research on the protective effects of rutin and its mechanisms in human are needed to confirm animal studies. Furthermore, some of the studies discussed in this review article did not follow a recent document outlining the best practices for pharmacological research on herbal bioactive preparations.

ACK N OWLED G M ENTS
The authors are thankful to Mashhad University of Medical Sciences.

CO N FLI C T O F I NTE R E S T
The authors declare that they have no conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
Data available on request from the authors.